The purpose of this study was to compare the dentin bond strength of three self-adhesive cements with smear layer pretreatments using a calcium-chelating agent (EDTA) and deproteinizing solution (NaOCl) and to evaluate their interfacial characteristics. Smear layer-covered dentin surfaces were pretreated with EDTA for 60 s, NaOCl for 5 and 15 s, or none. Three self-adhesive cements; Clearfil SA luting (Kuraray Medical), Rely X Unicem clicker (3M ESPE) and Breeze (Pentron) were applied to the dentin surfaces. After 24-h water storage, shear bond strengths to dentin were determined. In addition, nanoleakage evaluation at the interface was performed using FE-SEM and EDS. EDTA-pretreatment significantly improved the bond strength of BR (p<0.05) and NaOCl-pretreatment for 15 s significantly improved the bond strength of RX (p<0.05). On the other hand, for SA, both pretreatments significantly decreased bond strength to dentin (p<0.05). Nanoleakage formation was observed in various amounts at the cement-dentin interfaces.

The purpose was to evaluate the effect of air-drying dentin surfaces on the microtensile bond strength (μTBS) of a solvent-free onestep adhesive (Bond 1 SF). Twelve human molars were ground with 600-grit SiC paper. Before applying bonding agent, the dentin surface was rinsed with distilled water and blot-dried with tissue paper, followed by air-drying for 0, 3, 30, and 60 s using with a dental air syringe. After applying and curing Bond 1 SF, resin composite was incrementally built up. Specimens were then stored in distilled water for 24 h and then μTBSs were measured at a cross-head speed of 1 mm/min. Higher μTBS were observed when the dentin surface was air-dried for 3 s (33.2±6.8MPa)>0 s (26.7±4.5MPa)>30 s (22.6±5.5MPa)=60 s (20.4±5.0MPa). The results suggested that prolonged air-drying of the dentin surface removed water and decreased the bond strengths of Bond 1 SF.